Zellweger's Syndrome With PEX6 Gene Mutation in Mixteco Neonates Due to Possible Founder Effect

Zellweger spectrum disorder (ZSD) is a group of autosomal recessive peroxisomal disorders caused by PEX gene mutations that commonly present with symptoms of severe hypotonia, epileptic seizures, failure to thrive, hepatomegaly, craniofacial dysmorphisms, and sensorineural hearing loss. This article highlights three patients born with ZSD in Central California. All three patients were born to Mixteco mothers. Patients were genetically analyzed, which revealed mutations that correspond to ZSD. They presented with hypotonia at birth, abnormal hepatic panels, and increased fatty acid levels, findings consistent with Zellweger syndrome (ZS). However, only two of three patients displayed sensorineural hearing loss. Two of the patients failed to survive more than one year of age, which reflects the average life expectancy of an infant presenting with ZS. Observed and recorded cases of ZS in the Mixteco population have been postulated to be related to consanguinity and/or a founder effect. Studies have shown that autosomal recessive diseases are more prevalent in consanguineous populations. Consanguinity has been denied by patient 1 and is unknown for patients 2 and 3. Founder mutations have been implicated in areas with high rates of autosomal recessive diseases. All three of our Mixteco patients share a distinct lineage as well as a mutation at PEX6, leading us to believe that they suffered from an inherited founder mutation. The Mixteco population is not studied well enough to come to a definitive conclusion; however, the recognition of the relationship between ZS and Mixteco background is important, as it allows parents to plan accordingly and increases awareness in the community.